Scanners are used to scan an image to create a scanned image which can be displayed on a computer monitor, which can be used by a computer program, which can be printed, which can be faxed, etc. One conventional high-speed scanner includes a scan bar, an ASIC (application specific integrated circuit) controller, and a cable operatively interconnecting the controller and the scan bar. The scan bar includes a linear array of sensor (i.e., optical sensor) elements (such as CCD [charge-coupled-device] elements) substantially-aligned along the fast-scan axis. Each sensor element produces a signal proportional to the amount of light reaching the element.
In this conventional scanner, at time of scanner manufacture, the controller is adapted to generate a pattern of control signals including single-sensor control signals based upon the predetermined time delay for the single-sensor control signals to be sent from the controller through the cabling system (i.e., the cable and associated components such as shielding and connectors) to the scan bar. This scanner requires very tight manufacturing controls to be placed on the cabling system so that the cable system-induced time delay of the control signals will be the same for each manufactured scanner.
In this conventional scanner, at time of scanner manufacture, the controller is adapted to generate the single-sensor control signals to extract an analog output from each of the sensor elements based upon an analysis of the performance of a plurality of scanners. Such single-sensor control signals include a phase-clock high signal, a sensor-element reset signal, a sensor-element clamp signal, a sensor-element reference sample signal, and a sensor-element video sample signal. The same single-sensor control signals are used for each of the sensor elements of the scan bar.
What is needed is an improved method for adjusting a controller of a scanner.